Ron, I may have misunderstood you, but it seems like you are suggesting that the thin forearm, especially the area behind the pipe extension, is a flaw in either design or craftsmanship.
If you are pointing out that this technique leaves some relatively unsupported wood directly behind the pipe extension, then I would agree. If a shooter lays a rifle built this way across a tree branch or log a little too roughly, that area may collapse. That’s true.
But is that something that modern builders need to think of as a mistake? Do we need to correct for it, and leave a lot more wood in the forearm?
I am a traditionalist. I know that not everyone shares that philosophy, and I don't mean to imply that they should. But I enjoy the proportions of an elegant antique. If I build one just like the old guy built it, and it ends up wearing in the same places that his work showed wear, then I guess I think of that wear as patina. That said, I don’t mean to suggest that it’s a good idea to repeat bad design, or bad architecture, for example. But not every “weak area” that shows damage in an antique longrifle is bad design. Many of the eastern longrifles of this late period were somewhat weak in certain areas. They were thin, and elegant—and somewhat vulnerable as a result.